SAGA complex
Definition
Target type: cellularcomponent
A SAGA-type histone acetyltransferase complex that deubiquitinates H2A and/or H2B. This complex is organized into several functional submodules: a structural core including the activator binding module and consisting of ADA1 or a homolog, members of the SPT and TAF protein families as well as promotor recruitment factor TRRAP/TRA1, a histone acetyltransferase (HAT) module consisting of GCN5/KAT2A or PCAF/KAT2B, ADA2, ADA3/NGG1, and SGF29 or homologues thereof, a histone deubiquitinase (DUB) module consisting of ATXN7/SGF73, ATXN7L3/SGF11, ENY2/SUS1 and USP22/UBP8 or homologues thereof, and in some taxa a splicing module consisting of SF3B3 and SF3B5 or homologues thereof (not in fungi). In budding yeast also contains Spt8 which distinguishes it from SAGA-like (SLIK) complex (GO:0046695). [PMID:10637607, PMID:17337012, PMID:19056896, PMID:20838651, PMID:33004486]
The SAGA (Spt-Ada-Gcn5-acetyltransferase) complex is a multi-protein complex found in eukaryotes that plays a crucial role in gene transcription. It functions as a histone acetyltransferase (HAT) complex, modifying histones and influencing chromatin structure. The cellular component of the SAGA complex is primarily the nucleus, where it is localized and interacts with DNA and other nuclear proteins. The complex is dynamic and can associate with different regions of the genome depending on the cellular context. The SAGA complex contains several subunits with diverse functions, including:
- **Spt7:** A core subunit that interacts with the TATA-binding protein (TBP) and plays a role in transcription initiation.
- **Spt3:** Another core subunit that interacts with DNA and contributes to the stability of the complex.
- **Ada2:** A subunit involved in recruiting the complex to specific DNA sequences.
- **Gcn5:** The catalytic subunit responsible for histone acetylation.
- **Tra1:** A subunit involved in histone H3 acetylation and regulation of transcription.
- **Ubp8:** A deubiquitinase subunit that removes ubiquitin from histones, impacting chromatin structure.
- **Taf5:** A subunit that interacts with the TATA-binding protein (TBP) and plays a role in transcription initiation.
- **Taf9:** A subunit that interacts with the Spt3 subunit and contributes to the stability of the complex.
- **Taf10:** A subunit that interacts with the Ada2 subunit and helps recruit the complex to specific DNA sequences.
- **Taf12:** A subunit that interacts with the Gcn5 subunit and helps regulate histone acetylation.
- **Taf13:** A subunit that interacts with the Tra1 subunit and helps regulate transcription.
The SAGA complex also contains other subunits that are less well characterized but contribute to its overall function. These subunits include:
- **Spt20:** A subunit that interacts with the Spt7 subunit and contributes to the stability of the complex.
- **Spt21:** A subunit that interacts with the Spt3 subunit and contributes to the stability of the complex.
- **Spt22:** A subunit that interacts with the Ada2 subunit and helps recruit the complex to specific DNA sequences.
In summary, the cellular component of the SAGA complex is the nucleus, where it functions as a HAT complex, modifying histones and influencing chromatin structure. The complex is composed of multiple subunits with diverse functions, including core subunits, catalytic subunits, and regulatory subunits, all working together to regulate gene transcription.'
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Proteins (3)
| Protein | Definition | Taxonomy |
|---|---|---|
| Histone acetyltransferase KAT2B | A histone acetyltransferase KAT2B that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q92831] | Homo sapiens (human) |
| Histone acetyltransferase KAT2A | A histone acetyltransferase KAT2A that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q92830] | Homo sapiens (human) |
| Splicing factor 3B subunit 3 | A splicing factor 3B subunit 3 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q15393] | Homo sapiens (human) |
Compounds (17)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 4-aminophenol | 4-aminophenol : An amino phenol (one of the three possible isomers) which has the single amino substituent located para to the phenolic -OH group. 4-aminophenol: RN given refers to parent cpd | aminophenol | allergen; metabolite |
| embelin | embelin : A member of the class of dihydroxy-1,4-benzoquinones that is 2,5-dihydroxy-1,4-benzoquinone which is substituted by an undecyl group at position 3. Isolated from Lysimachia punctata and Embelia ribes, it exhibits antimicrobial, antineoplastic and inhibitory activity towards hepatitis C protease. embelin: from Embelia fruit (Myrsinaceae) | dihydroxy-1,4-benzoquinones | antimicrobial agent; antineoplastic agent; hepatitis C protease inhibitor; plant metabolite |
| plumbagin | plumbagin : A hydroxy-1,4-naphthoquinone that is 1,4-naphthoquinone in which the hydrogens at positions 2 and 5 are substituted by methyl and hydroxy groups, respectively. plumbagin: a superoxide anion generator | hydroxy-1,4-naphthoquinone; phenols | anticoagulant; antineoplastic agent; immunological adjuvant; metabolite |
| ferrocin c | N-methyl-2-quinolone: structure in first source | ||
| epigallocatechin gallate | (-)-epigallocatechin 3-gallate : A gallate ester obtained by the formal condensation of gallic acid with the (3R)-hydroxy group of (-)-epigallocatechin. epigallocatechin gallate: a steroid 5alpha-reductase inhibitor and antimutagen in green tea (Camellia sinensis) | flavans; gallate ester; polyphenol | antineoplastic agent; antioxidant; apoptosis inducer; geroprotector; Hsp90 inhibitor; neuroprotective agent; plant metabolite |
| coenzyme a | adenosine 3',5'-bisphosphate | coenzyme; Escherichia coli metabolite; mouse metabolite | |
| anacardic acid | anacardic acid : A hydroxybenzoic acid that is salicylic acid substituted by a pentadecyl group at position 6. It is a major component of cashew nut shell liquid and exhibits an extensive range of bioactivities. anacardic acid: isolated from Anacardium occidentale; monophenol monooxygenase inhibitor | hydroxy monocarboxylic acid; hydroxybenzoic acid | anti-inflammatory agent; antibacterial agent; anticoronaviral agent; apoptosis inducer; EC 2.3.1.48 (histone acetyltransferase) inhibitor; EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor; neuroprotective agent; plant metabolite |
| trichostatin a | trichostatin A: chelates zinc ion in the active site of histone deacetylases, resulting in preventing histone unpacking so DNA is less available for transcription; do not confuse with TRICHOSANTHIN which is a protein; found in STREPTOMYCES | antibiotic antifungal agent; hydroxamic acid; trichostatin | bacterial metabolite; EC 3.5.1.98 (histone deacetylase) inhibitor; geroprotector |
| tacrolimus | tacrolimus (anhydrous) : A macrolide lactam containing a 23-membered lactone ring, originally isolated from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis. Tacrolimus: A macrolide isolated from the culture broth of a strain of Streptomyces tsukubaensis that has strong immunosuppressive activity in vivo and prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro. | macrolide lactam | bacterial metabolite; immunosuppressive agent |
| 2-(3-Chloro-2-fluorophenyl)-2,3-dihydroisothiazol-3-one | organofluorine compound | ||
| guttiferone e | guttiferone E: isolated from the fruits of Garcinia pyrifera collected in Malaysia; structure in first source | ||
| lactacystin | lactam; S-substituted L-cysteine | ||
| 2-hydroxy-6-[(8Z,11Z)-pentadeca-8,11,14-trien-1-yl]benzoic acid | hydroxybenzoic acid | ||
| e 7107 | E 7107: has antineoplastic activity | ||
| 3-furancarboxylic acid, tetrahydro-4-methylene-5-oxo-2-propyl-, (2r,3s)-rel- | gamma-lactone | ||
| i-bet726 | |||
| 1,2-bis(isothiazol-5-yl)disulfane | 1,2-bis(isothiazol-5-yl)disulfane: structure in first source |